Pump system

ABSTRACT

A vacuum suspension system includes a foot cover having a heel portion and a pump system located in the heel portion. The pump system includes upper and lower sections arranged to move in an axial direction relative to one another and a pump mechanism operatively connected to and positioned between the upper and lower sections. When the heel portion is loaded in stance the pump mechanism moves from an original configuration in which the volume of a fluid chamber defined by the pump mechanism is zero or near-zero, to an expanded configuration in which the volume of the fluid chamber is increased.

TECHNICAL FIELD

The disclosure relates to the field of prosthetic devices, and moreparticularly to a prosthetic device, system and pump mechanism forincreasing vacuum in a vacuum assisted suspension system.

BACKGROUND

An ongoing challenge in the development of prosthetic devices is theattachment of the prosthetic device to the residual limb of a user. Forprosthetic legs, it is often difficult to securely attach the prostheticleg to the residual leg without exerting too much or uneven pressure onthe residual limb. On the one hand, the lack of a secure attachment canadversely affect the user's ability to walk. On the other hand, animproper fit can cause sores, swelling and pain for the user.

One approach for overcoming this challenge has been the application of anegative pressure vacuum in a space between the limb (or a liner donnedon the limb) and a socket or receptacle coupled to the prosthetic limb.Two conventional ways to apply such a vacuum are by a mechanical pump oran electronic pump.

Mechanical pumps are often in-line systems that utilize the movement ofthe user to generate the negative pressure vacuum in the socket. Forexample, the force generated by contacting the ground during a user'swalking motion can be used to generate a vacuum in the socket space tohold the prosthesis to the user's limb. However, in utilizing the motionof the user, known pumps rely on complete compression of the pump toexpel air from the pump before the pump can be decompressed to generatethe vacuum. Because the impact and displacement of the pump is notconsistent and varies between users, the vacuum and thus attachmentbetween residual limb and the socket can be unpredictable and/orinadequate, causing the user discomfort, grief and even injury.

Yet another drawback is that many known pumps are integrated into theprosthetic limb in such a way that any failure of the pump would greatlyimpair the user's ability to walk. Many of such pumps are also bulky andsignificantly contribute to the weight of the prosthetic limb, imposinga significant weight burden on the user when walking.

There is a need for a vacuum suspension system that provides freedom ofvacuum suspension for a prosthetic system. There is also a call for avacuum suspension system that provides a secure vacuum without losingsuction and confidence to the user over a period of user. It is alsodesirable for vacuum suspension systems to draw a vacuum while beinglightweight and streamlined.

SUMMARY

Embodiments of the vacuum suspension system provide vacuum assistedsuspension by generating negative pressure inside a prosthetic socketworn over a residual limb, and reducing sliding movement between theliner and the socket. The function of the embodiments is automatic as itis activated during gait. The weight placed on a prosthetic device ofthe system expands a pump mechanism that efficiently draws air out fromthe socket in each step, and expels it into the atmosphere during swingphase as the pump mechanism returns to an original configuration. Theprosthetic device can be the socket, a prosthetic pylon, a prostheticfoot, an adaptor system, a prosthetic knee, or any other suitabledevice.

The pump mechanism utilizes the user's loading on the prosthetic deviceto create negative pressure into the socket without substantiallyaffecting the functionality of the prosthetic device. It also does sowithout the use of complicated and bulky components as in the prior art,resulting in more secure and reliable elevated vacuum suspension.Furthermore, the pump mechanism can be a separate add-on module to theprosthetic system and can be adapted to fit a number of differentprosthetic devices, providing versatility.

According to an embodiment, the vacuum suspension system includes a pumpsystem arranged to be in fluid communication with a prosthetic socket.The pump system includes a pump mechanism having a housing and amembrane situated on the housing such that a fluid chamber is definedbetween the membrane and the housing. The pump mechanism is movablebetween an original configuration in which the volume of the fluidchamber is zero or near-zero, and an expanded configuration in which thevolume of the fluid chamber is increased.

According to a variation, the pump system comprises a prosthetic adaptoradapted to form at least part of a load bearing connection between aprosthetic foot and the prosthetic socket. The pump system can includeupper and lower sections arranged to move in an axial direction relativeto one another, and the pump mechanism operatively connected to andpositioned between the upper and lower sections such that when the pumpsystem is loaded in stance the pump mechanism moves from the originalconfiguration toward the expanded configuration.

During weight bearing (e.g., in stance phase), the upper section and thelower section move toward one another, which, in turn, moves the pumpmechanism toward the expanded configuration and increases the volume ofthe fluid chamber. This increase in the volume of the fluid chambercreates a vacuum in the pump mechanism, pulling fluid into the pumpmechanism from the socket. Weight bearing on the prosthetic connectorthus automatically creates a vacuum in the pump mechanism.

After weight bearing (e.g., in swing phase), the pump mechanism returnstoward the original configuration as the upper and lower sections moveaway from one another, expelling fluid within the fluid chamber. Thepump mechanism can thus generate a vacuum in the socket during stancewithout undesirably affecting the functionality of the prosthetic footor significantly increasing the bulk of the prosthetic device. Inaddition, the pump mechanism 126 can advantageously provide a dampeningor shock absorbing effect to the prosthetic device, allowing for a morecomfortable gait cycle.

According to a variation, the pump mechanism can be located at or nearthe socket such that there is no need to move fluid drawn into the pumpmechanism from the socket down to the prosthetic foot. Thisadvantageously reduces the time required to produce an elevated vacuumin the socket. Further, it eliminates or reduces the need of a long tubeextending between the pump mechanism and the socket, reducing thelikelihood of leaks and volume to generate vacuum. The pump mechanismembodiments can also be formed to be used with both left and rightprosthetic feet or may be foot specific.

According to a variation, the pump system can include a biasingmechanism arranged to bias the pump mechanism toward the originalconfiguration. When the pump system is loaded, the biasing mechanism cancompress between the upper and lower sections. When the pump system isunloaded, the biasing mechanism decompresses and stored energy in thebiasing mechanism drives the pump mechanism toward the originalconfiguration.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood regarding the followingdescription, appended claims, and accompanying drawings.

FIG. 1 shows a side view of a vacuum suspension system according to anembodiment.

FIG. 2 shows a detailed side view of the pump system in FIG. 1.

FIG. 3 shows another detailed side view of the pump system in FIG. 1.

FIG. 4 shows partial cutaway view of the vacuum suspension system inFIG. 1.

FIG. 5 shows a side isometric view of a vacuum suspension systemaccording to an embodiment.

FIG. 6 shows a front view of the pump system in FIG. 5.

FIG. 7 shows a cross section view of the pump system in FIG. 5.

FIG. 8 shows another cross section view of the pump system in FIG. 5.

FIG. 9 shows a side isometric view of a vacuum suspension systemaccording to another embodiment.

FIG. 10 shows a side isometric view of the pump system in FIG. 9.

FIG. 11 shows a cross section view of the pump system in FIG. 9.

FIG. 12 shows another cross section view of the pump system in FIG. 9.

FIG. 13 shows a side isometric view of a pump system according toanother embodiment.

FIG. 14 shows a cross section view of the pump system in FIG. 13.

FIG. 15 shows another cross section view of the pump system in FIG. 13.

FIG. 16 shows a side isometric view of a pump system according toanother embodiment.

FIG. 17 shows a cross section view of the pump system in FIG. 16.

FIG. 18 shows another cross section view of the pump system in FIG. 16.

FIG. 19 shows a side isometric view of a pump system according toanother embodiment.

FIG. 20 shows a cross section view of a pump system according to anotherembodiment.

FIG. 21 shows another cross section view of the pump system in FIG. 20.

FIG. 22 shows a side view of a pump system according to anotherembodiment.

FIG. 23 shows a cross section view of the pump system in FIG. 22.

FIG. 24 shows another cross section view of the pump system in FIG. 22.

FIG. 25 shows a cross section view of a pump system according to anotherembodiment.

FIG. 26 shows another cross section view of the pump system in FIG. 25.

FIG. 27 shows a side isometric view of a vacuum suspension systemaccording to another embodiment.

FIG. 28 is a cross section view of the vacuum suspension system in FIG.27.

FIG. 29 shows a partial side isometric view of a vacuum suspensionsystem according to another embodiment.

DETAILED DESCRIPTION OF THE DISCLOSURE

It will be understood that, unless a term is expressly defined in thisdisclosure to possess a described meaning, there is no intent to limitthe meaning of such term, either expressly or indirectly, beyond itsplain or ordinary meaning.

Any element in a claim that does not explicitly state “means for”performing a specified function, or “step for” performing a specificfunction, is not to be interpreted as a “means” or “step” clause asspecified in 35 U.S.C. § 112, paragraph 6.

The embodiments of one or more components of a vacuum suspension systemwill be described. A pump system having a fluid connection with a socketassists in creating a vacuum between a residual limb and the socket bypumping fluid out of the socket. The fluid can be pumped out of thesocket when the user puts his weight on a prosthetic device (e.g., aprosthetic foot, a pylon, or prosthetic knee). The user's load on theprosthetic device can cause a pump mechanism of the pump system toincrease the volume of a fluid chamber in the pump mechanism. Theincrease in volume of the pump mechanism draws in fluid from the vacuumspace between the residual limb and the socket of a prosthetic limb. Inthis manner, the pump mechanism decreases the air pressure within thevacuum space causing a vacuum effect.

After the load is removed, and/or shifted on the prosthetic device, thevolume of the fluid chamber in the pump mechanism is automaticallydecreased. The connection between the vacuum space and the pumpmechanism may have a one-way valve assembly, so all of the air withinthe volume of the pump mechanism is expelled out of an outlet to anotherspace or to atmosphere. The outlet is provided with a one-way valveassembly so the vacuum space is the only source of air.

The vacuum suspension system of the present disclosure produces a vacuumeffect in a prosthetic socket that is advantageous over prior artdevices that require compression of the pump to expel air before thepump can be decompressed to draw in air. The present disclosure alsoachieves smaller fluctuations in air pressure than the prior artsystems, so the difference between the greatest pressure and lowestpressure in the vacuum space of the socket is less.

The pump mechanism embodiments may easily retrofit on existingprosthetic devices and can do so without undesirably affecting theirfunction. They are also lightweight and low-profile, advantageouslycontributing little to no bulk to a prosthetic foot. Optionally, thepump mechanism embodiments can be located at or near the socket suchthat there is no need to move fluid drawn into the pump mechanism fromthe socket down to the prosthetic foot. This advantageously reduces thetime required to produce an elevated vacuum in the socket. Further, iteliminates or reduces the need of a long tube extending between theprosthetic foot and the socket, reducing the likelihood of leaks andvolume to generate vacuum. The pump mechanism embodiments can also beformed to be used with both left and right prosthetic feet or may befoot specific.

The efficiency of the pump mechanism is determined at least in part byhow effectively the volume of the fluid chamber is reduced. Since thepump mechanism begins at and returns to the original state of zero ornear-zero volume at the beginning or end of each cycle in someembodiments, the volume of the fluid chamber is determined by the forceapplied to the pump, not by a full compression and recompression cycleas in the prior art. In addition, all fluid drawn into the pumpmechanism is expelled afterwards, fully utilizing the volume of thefluid chamber.

The vacuum suspension system also reduces volume fluctuations of theresidual limb and allows for increased proprioception and reducedpistoning since there is a better attachment between the socket and theresidual limb. It may also be beneficial to produce hypobaric pressurebelow a certain level in the socket. This may be achieved using asealing membrane or seal component between the residual limb and thesocket, instead of the conventional sealing method of using a sleeve toform an airtight connection between the residual limb and the proximalend of the socket. The sealing membrane may be on a prosthetic liner asdescribed in U.S. Pat. No. 8,034,120 incorporated by reference andbelonging to the assignee of this disclosure.

The benefit of using a liner having a seal or seal component reduces thevolume of air to be drawn out of the socket and therefore, a bettersuspension may be achieved in a shorter time period. Using a siliconeliner with integrated seal also provides the added benefit that thehypobaric region is not directly applied to the skin.

The vacuum pump mechanisms in the embodiments of the prosthetic devicedescribed are generally described as a pump system or mechanism and mayinclude any suitable type of pump mechanism. For instance, the pumpmechanism may be a pump as described in U.S. provisional application62/019,674 incorporated by reference and belonging to the assignee ofthis disclosure. A piston-type pump may be used in the embodiments inplace of a membrane-type pump. A bladder-type pump may also be used inthe embodiments in place of a membrane-type pump, and a skilled personwould understand that the pump mechanisms described may also be usedwith a bladder-type pump and vice versa.

A bladder-type pump has an interior fluid chamber surrounded by anairtight material. When the interior chamber is expanded, the opposingwalls are moved away from each other by extending at least one side wallof the pump. The side walls of the bladder-type pump may have anaccordion-like shape or be formed of a polymeric material which allowfor the increase in distance between the opposing walls.

A membrane-type pump has at least one wall of flexible material and asecond opposing wall which may be rigid or flexible. The edges of thetwo walls are attached to each other such that when a force applies tothe pump to expand the interior fluid chamber, the force deforms atleast the flexible wall, and the flexible wall arcs outward to form aninterior fluid chamber. To allow for deformation, the flexible wall maybe made of a polymeric material including elastomeric material such asrubber or plastic.

The bladder-type pump and membrane-type pump are arranged so that whenno force applies to the pump or no weight is placed on the prostheticdevice the volume of the interior fluid chamber is zero or near-zero.The pumps described and shown have a cylindrical shape. A skilled personwould understand that the pumps may have a variety of shapes, forexample, a diamond, rectangular, or triangular shape.

The specific embodiments of the prosthetic device will now be describedregarding the figures.

FIGS. 1 and 2 show a vacuum suspension system 1 comprising a pump system2 and a prosthetic foot 4 according to an embodiment. As seen in FIG. 1,the prosthetic foot 4 can be any suitable prosthetic foot but is shownhaving a foot member 6 that extends from a proximal section 8terminating at a proximal end to a distal section 10 terminating at adistal end. The proximal section 8 can be generally vertically oriented,and the distal section 10 can be generally horizontally oriented.

The foot member 6 can have a curved portion 12 between the proximalsection 8 and the distal section 10 that is generally forwardly-facingconcave. The curved portion 12 and/or the proximal section 8 can begenerally at a location of a natural human ankle. The prosthetic foot 4can have a heel member 14 that extends rearwardly from the foot member 6and is disposed below at least a portion of the foot member 6. The heelmember 14 can have a curvilinear profile along its length.

An adaptor 16 can be coupled to the anterior surface of the proximalsection 8 of the foot member 6. Advantageously, the adaptor 16 can havea hole 18 or a hollowed-out portion to reduce the weight of the adaptor16. An adhesive or bonding agent (e.g., epoxy) can be applied to theproximal section 8 or the posterior surface of the adaptor 16 to securethe adaptor 16 to the proximal section 8 of the foot member 6.Alternatively, fasteners or other hardware can be used to secure theadaptor 16 to the foot member 6.

A connector 20 can be disposed on the proximal end of the adaptor 16 forcoupling the foot member 6 to a prosthetic pylon 22 or socket. Theconnector 20 can be a male pyramid connector, a tube clamp, or otherattachment device. The connector can be secured to the adaptor 16 withadhesive or bonding agent. The connector 20 can also be secured to theadaptor 16 with fasteners or other hardware. Additionally, oralternatively, the connector 20 can be threadedly attached to theadaptor 16.

In use, the prosthetic foot 4 can expand and compress. The prostheticfoot 4 is in expansion when the proximal end of the foot member 6 andthe heel member 14 are moved together from a resting position of thefoot, reducing the distance between the foot member and the heel member.The prosthetic foot 4 is in compression when the proximal end of thefoot member 6 and the heel member 14 are moved apart from the restingposition of the foot, increasing the distance between the foot memberand heel member 14.

Additional prosthetic foot designs that can include the pump systemembodiments disclosed herein can include, but are not limited to, thefollowing models by Össur of Rektavik, Axia™, Ceterus™, Elation™, LPCeterus™, LP Vari-Flex™, Modular III™, Re-Flex VSP®, Cheetah™,Flex-Sprint™, Flex-Run™, Talux®, Vari-Flex®, Flex-Foot® Junior,Sure-Flex, Vari-Flex XC Rotate™, LP Rotate™, LP Re-Flex VSP, Re-FlexRotate™, Re-Flex Shock™, Flex-Foot Balance, Flex-Foot Assure, andBalance™ Foot J. This disclosure is incorporated by reference andbelongs to the assignee of this disclosure.

Optionally, the prosthetic foot 4 may be insertable into a foot cover 24as seen in FIG. 1. The bottom surface of the foot member 6 and/or a rearsurface of the heel member 14 can be shaped to generally correspond tothe curvature and shape of the inner surfaces of a foot cover.

In order to better understand the operation of the prosthetic foot 4, abasic discussion of the gait cycle is required. The gait cycle definesthe movement of the leg between successive heel contacts of the samefoot. The gait cycle has two phases: stance and swing. Of particularinterest is the stance phase which generally includes heel-strike orinitial contact, mid-stance, and toe-off.

It is during the stance phase that the mechanics of a prosthetic foot 4come into play. Upon heel strike, the prosthetic foot 4 is in expansion,providing cushioning to the user. During mid-stance, at which time theweight of the user is transmitted through the prosthetic foot 4 to asupporting surface, the prosthetic foot 4 moves from expansion intocompression. The prosthetic foot 4 remains in compression throughtoe-off until the weight of the user is removed from the prostheticfoot, at which time the prosthetic foot 4 returns to its restingposition.

The pump system 2 can be coupled to the prosthetic device at anysuitable location but is shown coupled between the heel member 14 andthe pylon 22. The pump system 2 can be formed to be used with both leftand right prosthetic feet. Alternatively, the pump system 2 can beformed to be used specifically on a left or right prosthetic foot.

The pump system 2 can include a pump mechanism 26 made generally fromcarbon fiber and/or plastic, and an elastomeric compound (e.g., amembrane) providing durable yet lightweight components. Prior art pumpmechanisms are of heavy metal construction, which imposes a significantweight burden on the user when walking.

The pump mechanism can be secured to the pylon 22. For instance, thepump mechanism 26 can be located between a support member 28 extendingrearwardly from the pylon 22 and a movable member 30 connected to thepylon 22 below the support member 28. Because the pump mechanism issecured to the pylon 22, it advantageously does not add volume to theprosthetic foot 4 and/or foot cover 24.

The pump mechanism 26 includes a housing 32 containing one or more valveassemblies 34, a membrane 36, a connector 38, and a connecting system40. The one or more valve assemblies 34 can include a one-way valve,also referred to as a check valve. A preferred type of one-way valveused is a duckbill valve. It should be appreciated however that othertypes of one-way valves are possible.

The one or more valve assemblies 34 can include an inlet valve assemblyarranged to only allow fluid to enter the pump mechanism 26 and canoptionally be connected to a tube. The pump mechanism 26 can be in fluidcommunication with the cavity of a prosthetic socket. When the volume ofthe pump mechanism 26 increases, fluid (e.g., air) can be drawn out fromthe socket via the inlet valve assembly. The at least one valve assembly34 can include an outlet valve assembly arranged to only allow fluid tobe expelled out of the pump mechanism 26, preferably to atmosphere. Theoutlet valve assembly may include a silencer.

Because the pump mechanism 26 is located away from the foot 4 and towardthe socket, there is no need to move the fluid drawn into the pumpmechanism from the socket down to the prosthetic foot, advantageouslyreducing the time required to produce an elevated vacuum in the socket.Further, it eliminates the need of a long tube extending between theprosthetic foot and the socket and the likelihood of leaks in the pumpsystem 2.

Referring to FIG. 2, the top surface of the housing 32 defines a cavity42 that is provided with an undercut circumferential groove 44 betweenan open end of the cavity 42 and a closed bottom of the cavity. An outerradial edge of the membrane 36 can be situated in the circumferentialgroove 44 such that a seal is formed between the membrane 36 and thehousing 32. Optionally, an adhesive can be applied between the housing32 and the outer radial edge of the membrane 36, increasing the sealingeffect. The bottom of the cavity has one or more openings 46 whichextend into the housing 32 to form internal passageways providing fluidcommunication between a fluid chamber 48 defined between the bottom ofthe cavity and a bottom surface of the membrane 36, and the at least onevalve assembly 34.

The pump mechanism 36 relies upon deformation of the membrane 36 to movebetween an original configuration (shown in FIG. 2) in which the volumeof the fluid chamber 48 is zero or near-zero, and an expandedconfiguration (shown in FIG. 3) in which the volume of the fluid chamber48 is increased.

When a force F is exerted on the membrane 36 in a direction away fromthe housing 32, the pump mechanism 26 moves toward the expandedconfiguration (shown in FIG. 3) as the force F pulls the bottom of thecavity away from a portion of the membrane 26, causing deformation ofthe membrane 36 and an increase in volume of the fluid chamber 48. Thisincrease in volume of the fluid chamber 48 can draw fluid into the fluidchamber from the socket through the one or more valve assemblies 34. Thehousing 32 may be formed of metal such as stainless steel, carbon fiber,or plastic or any other material which would provide sufficient strengthto resist deformation when pulled away from the membrane 36.

Once the force is removed from the membrane 36, the pump mechanism 26returns toward its original configuration (shown in FIG. 2) as themembrane 36 returns toward the bottom of the cavity and fluid within thefluid chamber 48 is expelled out of the one or more valve assemblies 34.The membrane 36 can be elastomeric and can use at least in part itsmaterial properties to naturally or elastically return to its originalposition on the bottom of the cavity.

The membrane 36 may have any desired shape, but is shown having agenerally circular or elliptical shape. The membrane 36 can beoperatively attached at or near its center point to the support member28 while the outer radial edge portion of the membrane 36 is attached tothe housing 32 such that when the housing 32 is pulled away from themembrane 36 a pocket forms in a middle area of the membrane 36 due tothe deformation of the membrane 36. The formation of the pocketincreases the volume of the fluid chamber 48. The pump mechanism 26 thususes a compliant membrane to create suction.

As seen in FIG. 2, the connector 38 can be an insert having a lowerradial flange 50 embedded in the membrane 36 and a shaft portion 52extending between the lower flange 50 and support member 28. In someembodiments, the connector 38 may be of a two-piece construction suchthat the shaft portion 52 can be threadedly removed from the lowerflange embedded in the membrane 36. The connector 38 may be formed ofmetal, plastic, or any suitable other material. In other embodiments,the lower flange may extend substantially into the membrane 36 or may beformed of a material that is part of the membrane 36 (e.g. a flexiblemetal member).

Other examples of the pump mechanism are described in U.S. patentapplication Ser. Nos. 13/873,394; 13/873,315; 13/766,086; 62/101,154;and 62/151,518, and commercially available as the Unity Vacuum System byÖssur hf. This disclosure is incorporated by reference and belongs tothe assignee of this disclosure.

The support member 28 can include a generally upright section 42attached to the pylon 22 and a generally horizontal section 44 extendingrearwardly from the section 42 and connected to the membrane 36 via theconnector 38. The sections 42, 44 can extend at any suitable anglerelative to the pylon 22.

The support member 28 can define an opening or slot for receiving theconnector 38. To attach the support member 28 to the membrane 36, theshaft portion of the connector 38 can be received in the opening or slotsuch that the section 44 of the support member 28 is connected to theconnector 38. The connector 38 can be threadedly attached to the supportmember 28. The connector 38 can be attached to the support 38 via a pin,nut, or other fastener. Through the structure of the connector 38 andthe support member 28, the pump mechanism 26 has the benefit of beingeasily and quickly removed and/or replaced from the prosthetic foot 4.

The movable member 30 can be secured to the pylon 22 at a location belowthe support member 28 and movable relative to the support member 28. Themovable member 30 can be a plate pivotally connected to the pylon 22 ata pivot point 54. In other embodiments, the movable member 30 can be aplate arranged to flexibly rotate relative to the support member 38.

The membrane 36 can rest within an opening 56 defined in the movablemember 30. The housing 32 can have a portion which extends beyond themembrane 36 to engage the bottom surface of the movable member 30surrounding the opening 56 and allows the movable member 30 to pull thehousing 32 away from the membrane 36 when flexed.

Referring to FIGS. 3 and 4, a tensioning system 58 operatively connectsthe pump mechanism 26 to the prosthetic foot 4. The tensioning system 58can include a tensioning element 60 that is secured to and adjusted by atensioning control mechanism 62 to adjust the length of the tensioningelement 60. The tensioning element 60 can be a cable, a lace, wire orany other suitable member and may refer to a relatively long andrelatively thin shaped metals or polymers, which may be single strand ormulti-strand, and which may include friction reducing coatings thereon.The tensioning element 60 translates action of the prosthetic foot 4 tothe pump mechanism 26.

The tensioning control mechanism 62 can be a dial-tensioning controlmechanism arranged for incremental and preselected adjustment in thetension of the tensioning element 60. The tensioning control mechanism62 is not limited to the example provided above but can include anysystem that permits adjusting tension in the tensioning element 60. Thetensioning control mechanism 62 also allows the tensioning element 60 tobe fixed at a desired length.

The dial-tensioning control mechanism 62 can be secured to the posteriorsurface of the proximal section 8 of the foot member 6, with thetensioning element 60 extending from both the proximal and distal sidesof the dial-tensioning control mechanism 62. It should be noted that theends of the tensioning element 60 can be retained within thedial-tensioning control mechanism 62 and the portion of the tensioningelement 60 outside the dial-tensioning control mechanism 62 extendscontinuously between the connecting system 40, the heel member 14, andthe dial-tensioning control mechanism 62 without interruption.

As seen, the connecting system 40 of the pump system 2 can include atleast one arm member 64 attached to the housing 32. The arm member 64can include a first portion extending rearwardly from the housing 32 anda second portion curving downwardly toward the heel member 14.

A first end of the tensioning element 60 is attached to thedial-tensioning control mechanism 62. From the dial-tensioning controlmechanism 62, the tensioning element 60 extends through the connectingsystem 40. From the connecting system 40, the tensioning element 60extends downwardly toward the heel member 14. The tensioning element 60then passes an anchor point 66 on the heel member 14 which in turndirects the tensioning element 60 back toward the dial-tensioningcontrol mechanism 62. At the dial-tensioning control mechanism 62, asecond end of the tensioning element 60 is attached to thedial-tensioning control mechanism 62.

Because only the tensioning element 60 is attached to the prostheticfoot 4, the likelihood of the pump system 2 undesirably affecting theprosthetic foot 4 is advantageously reduced.

When the prosthetic foot 4 is in the resting position (shown in FIG. 1),the pump mechanism 26 is in its original configuration. Upon heelstrike, the prosthetic foot 4 moves into expansion, which, in turn,creates slack in the tensioning element 60. With the prosthetic foot 4in expansion, the pump mechanism 26 remains in its originalconfiguration.

As the prosthetic foot 4 moves from heel strike through mid-stanceand/or toe-off, the prosthetic foot 4 moves into compression. Incompression, the proximal end of the foot member 6 moves away from theheel member 14 causing the tensioning element 60 to tighten and apply adownward or pulling force on the connecting system 40 of the pump system2 as shown in FIG. 4.

The downward force on the connecting system 40 causes the housing 32 andthe movable member 30 to pivot and/or flex away from the support member28. This moves the housing 32 away from the membrane 36, moving the pumpmechanism 26 to the expanded configuration. More particularly, thesupport member 28 pulls the housing 32 away from the membrane 36,increasing the volume of the fluid chamber 48. Optionally, a springmember may be serially connected to the tensioning element 60 whichallows for movement without changing the stiffness of the prostheticfoot 4 too much. Further, the spring member can also reduce thelikelihood of the tensioning element 60 pulling too hard on the pumpmechanism 26.

This increase in volume of the fluid chamber 48 creates a vacuum in thepump mechanism 26, pulling fluid into the pump mechanism 26 through theone or more valve assemblies 34. Compression of the prosthetic foot thusautomatically creates a vacuum in the pump mechanism 26. This isadvantageous over prior art prosthetic devices that require compressionof the pump to expel air before the pump can be decompressed to draw inair. Further, because the pump mechanism 26 does not need to be firstcompressed before it can create a vacuum upon decompression, the pumpmechanism 26 can achieve smaller fluctuations in air pressure than theprior art devices, so the difference between the greatest pressure andlowest pressure in the vacuum space of the socket is less than comparedto the prior art devices.

At the end of the stance phase or when the weight of the user is removedfrom the prosthetic foot 4, the prosthetic foot 4 returns to its restingposition and a biasing mechanism 68 extending between the pylon 22 andthe connecting system 40 can help return the movable member 30 to itsresting position, moving the pump mechanism 26 back toward its originalconfiguration and decreasing the volume of the fluid chamber to a zeroor near zero volume.

During the return of the membrane 36 toward the housing 32, the pumpmechanism 26 expels fluid in the fluid chamber 48 out of the one or morevalve assemblies 34. Because of the pump mechanism 26 returns to itsoriginal configuration of zero or near-zero volume in the fluid chamberat the beginning or end of each gait cycle, substantially all fluiddrawn into the pump mechanism 26 is automatically expelled. This isadvantageous because prior art devices rely on complete compression ofthe pump in expelling air in each gait cycle to use the pump to itsmaximum capacity. It is difficult for complete compression to occur inevery cycle using the gait of a user as the actuating force since theimpact and displacement of the pump is not consistent and varies betweenusers.

The dial-tensioning control mechanism 62 may be rotated in a firstdirection to decrease the length of the tensioning element 60 andthereby increase the tension in the tensioning element 60. To increasethe length of the tensioning element 60 and thereby decrease the tensionin the tensioning element 60, the dial-tensioning control mechanism 62may be rotated in a second direction.

By adjusting the tension in the tensioning element 60, the sensitivityof the pump mechanism 26 can be varied. For instance, by increasing thetension in the tensioning element 60, the level of pre-load applied tothe housing 32 may be increased, increasing the sensitivity of the pumpmechanism 26 to the action of the prosthetic foot 4, It will beappreciated that the sensitivity of the pump mechanism 26 may be variedbased on user activity level, weight, and/or other factors,advantageously providing greater control and versatility.

FIGS. 5-8 show a prosthetic device or a vacuum suspension system 70including a pump system 72 according to another embodiment. The vacuumsuspension system 70 has a socket 76, a liner 78 preferably including aseal component, and a prosthetic foot 74. The socket 76 defines aninterior space, and an interior wall delimiting the interior shape. Thevacuum suspension system 70 includes an adapter system 80 for couplingthe socket 76 to a prosthetic pylon, prosthetic foot, a rotation module,a shock module, or other suitable component.

The vacuum suspension system 70 provides improved proprioception andvolume control. The vacuum suspension system 70 includes a pumpmechanism 82, as discussed in earlier embodiments, which provides avacuum assisted suspension by generating a negative pressure (vacuum)inside the socket 76. As seen, the pump mechanism 82 can be attacheddirectly to the socket 76.

An actuator comprising a cable member 104 extends between the pumpmechanism 82 and a heel member of the prosthetic foot 74. Because thepump mechanism 82 is located on the socket 76, fluid drawn into the pumpmechanism 82 from the socket 76 does not have to be drawn down to theprosthetic foot 74, advantageously increasing efficiency and reducingthe time required to produce an elevated vacuum in the socket 76.

Referring to FIGS. 6-8, the pump mechanism 82 includes a housing 84containing two one-way valve assemblies 86, 88, a membrane 90, and aconnector 92. The valve assembly 86 is arranged to only allow fluid toenter the pump mechanism 82, which can be in fluid communication withthe cavity of the socket 76. The valve assembly 88 is arranged to onlyallow fluid to be expelled out of the pump mechanism 82, preferably toatmosphere. The connector 92 is connected to the membrane 90 andincludes an attachment portion 94 above the membrane 90, and a shaftportion extending from the membrane 90 to the attachment portion. Thehousing 84 can include at least one fastener hole 96 arranged to receiveat least one fastener for attaching the pump mechanism 82 to the socket76.

FIGS. 7 and 8 show cross section views of the pump mechanism 82. Similarto the pump mechanism 26, the pump mechanism 82 relies upon deformationof the membrane 90 to move between an original configuration (shown inFIG. 7) in which the volume of a fluid chamber 98 defined between thetop surface of the membrane 90 and the bottom of the housing 84 is zeroor near-zero, and an expanded configuration (shown in FIG. 8) in whichthe volume of the fluid chamber 98 is increased. The membrane 90 can bepositioned in a cavity of the housing 84. The housing 84 surrounds theouter radial edge portion of the membrane 90 and creates a seal with themembrane 90. For instance, the cavity is provided with an undercutcircumferential groove 87 within which the outer radial edge of themembrane 90 is situated.

The bottom surface of the cavity defines a pair of openings 102 whichextend into the housing 84 to form internal passageways to provide fluidcommunication between the fluid chamber 98 and the two one-way valveassemblies 86, 88.

As seen in FIG. 5, the cable 104 is connected at a first end to theconnector 92 and at a second end to anchor point 106 on the prostheticfoot 74. Because only the cable 104 is attached to the prosthetic foot74, the likelihood of the pump system 82 undesirably impeding action ofthe prosthetic foot 74 is advantageously reduced. Further, the pumpsystem 82 does not add additional volume to the prosthetic foot 74and/or a foot cover.

Referring to FIGS. 7 and 8, the cable 104 can include a core 108slidably positioned within a tubular casing or sheath 110. The sheath110 is arranged to provide axial stiffness to the core 108 such that aforce on the second end of the cable 104 forces the core 108 upward ordownward relative to the sheath 110, moving the pump mechanism 82between the original configuration and the expanded configuration.Optionally, the cable 104 can be wrapped around the adaptor system 80and/or another component extending between the socket 76 and the adaptorsystem 80.

The function of the vacuum suspension system 70 can be fully automatic.During mid-stance and/or toe-off, compression of the prosthetic foot 74causes the cable 104 to pull the membrane 90 away from the housing 84,which, in turn, expands the pump mechanism 82 to efficiently draw fluidout of the socket 76. During the swing phase, decompression of theprosthetic foot 74 permits the pump mechanism 82 to return to itsoriginal position, expelling the fluid drawn from the socket 76 toatmosphere. The pump mechanism 82 thus can create a negative pressureinside the socket 76, resulting in a secure and reliable elevated vacuumsuspension that provides an intimate suspension as the negative pressureformed inside of the socket 76 holds the liner and the residuum firmlyto the socket wall.

FIGS. 9-12 show a prosthetic device or a vacuum suspension system 110including a pump system 112 according to another embodiment. The vacuumsuspension system 110 has a socket 114, a valve 116, and a tube 118connecting a pump mechanism 126 of the pump system 112 to the socket114, and a prosthetic foot 120. The vacuum suspension system 110includes an adaptor system 124 for coupling the socket 114 to aprosthetic pylon 122 attached to the prosthetic foot 120.

The vacuum suspension system 110 includes the pump system 112, asdiscussed in earlier embodiments, which provides a vacuum suspension bygenerating a vacuum inside the socket 114. As seen, the pump system 112can comprise a prosthetic connector adapted to form at least part of aload bearing connection between the foot 120 and the socket 114. Forinstance, the prosthetic connector can connect the socket 114 to thepylon 122, which is attached to the foot 120. As such, the pump system112 can help support loads exerted on the socket 114 and transfer suchloads to the ground or other underlying surface via the pylon 122 andthe foot 120. The pump system 112 can easily retrofit on existingprosthetic devices and can be formed for right and left prostheticdevices. For instance, the pump system 112 can easily retrofit on anexisting prosthetic device by selecting a pylon compatible with the pumpsystem 112. The pump system 112 can be substantially in axial alignmentwith the pylon 122.

Because the pump mechanism 126 of the pump system 112 can be located ator near the socket 114, fluid drawn from the socket 114 by the pumpmechanism 126 does not have to be moved down to the foot 122. This hasthe effect of reducing the time required to generate an elevated vacuumin the socket 114. This also reduces the length of the tube 118,reducing the likelihood of leaks in the pump system 112. It furtherhelps reduce the overall volume of the pump system 112. In otherembodiments, the pump mechanism 126 can be integrated into theattachment between the prosthetic foot 120 and another component. Inother embodiments, the pump mechanism 126 can be integrated into aprosthetic pylon 122.

Referring to FIGS. 10-12, the pump system 112 includes an upper section130, a lower section 132, and a pump mechanism 126. The upper section130 and the lower section 132 are arranged to move in an axial directionrelative to one another. The upper section 130 can define an adaptor 134having a female configuration arranged to receive a male adaptor, atube, or other component. The lower section 132 can define an adaptor136 having a similar configuration. In other embodiments, the adaptors134, 136 can be male adaptors or other type of connectors.

The upper section 130 defines a cavity 138 having a peripheral internalcavity wall 140 extending between a bottom opening 142 at or near thebottom of the upper section 130 and a closed end 144 (shown in FIG. 11).The cavity 138 is shown having a generally cylindrical shape but canhave any suitable shape. A pin member 146 protrudes downward from theupper wall 144 of the cavity 138. The pin member 146 can have a hollowconfiguration defining an internal channel extending through the pinmember 146.

The upper section 130 includes valve assemblies 160, 162. The valveassembly 160 is arranged to only allow fluid to enter the pump mechanism126 and can be connected to the tube 118. The valve assembly 162 isarranged to only allow fluid to be expelled out of the pump mechanism126, preferably to atmosphere. An internal passageway 152 is arranged toprovide fluid communication between the valve assemblies 160, 162 andthe pin member 146. Optionally, a lower end section of the pin member146 can define one or more perforations providing fluid communicationbetween the internal passageway 152 and a fluid chamber defined below.

The lower section 132 is sized and configured to fit into the cavity 138of the upper section 130 via the bottom opening 142. The lower section132 defines a cavity 154 to accommodate a membrane described below.

The pump mechanism 126 includes a housing 148 and a membrane 152. Thehousing 148 defines a through opening 150 arranged to allow the pinmember 146 to slidably pass therethrough. The housing 148 can have arigid configuration. The membrane 152 is positioned below the housing148. The cavity 154 can be dimensioned to allow a center portion of themembrane 152 to move in a downward direction within the lower section132 when the membrane 152 is pushed downward by the pin member 146 asdescribed below.

An outer radial edge of the membrane 152 can be attached to the housing148 such that a seal is formed between the membrane 152 and the housing148. Optionally, an adhesive can be applied between the housing 148 andthe outer radial edge of the membrane 152, increasing the sealingeffect. The fluid passageway 152 can be in fluid communication with afluid chamber 158 defined between the upper surface of the membrane 152and the bottom of the housing 148.

Similar to the other embodiments, the pump mechanism 126 relies upondeformation of the membrane 152 to move between an originalconfiguration (shown in FIG. 11) in which the volume of the fluidchamber 158 is zero or near-zero, and an expanded configuration (shownin FIG. 12) in which the volume of the fluid chamber 158 is increased.

During weight bearing (e.g., in stance phase), the pump mechanism 126moves toward the expanded configuration (shown in FIG. 12). Moreparticularly, the upper section 130 and the lower section 132 movetoward one another, which, in turn, causes the pin member 146 to pushthe center portion of the membrane 152 away from the bottom of thehousing 148, increasing the volume of the fluid chamber 158. Thisincrease in volume of the fluid chamber 158 creates a vacuum in the pumpmechanism 126, pulling fluid into the pump mechanism 126 through theinlet valve assembly 160. Weight bearing on the prosthetic connectorthus automatically creates a vacuum in the pump mechanism 126.

After weight bearing (e.g., in swing phase), the pump mechanism 136returns toward the original configuration (shown in FIG. 11) as theupper and lower sections 130, 132 move away from one another. This movesthe pin member 146 away from the membrane 152, allowing the membrane 152to return toward the bottom of the housing 148 and to expel fluid withinthe fluid chamber 158 out of the valve assembly 162. Optionally, the pinmember 146 can be attached to the membrane 152 such that it can pull themembrane 152 back to its original position after weight bearing.

It will be appreciated that the membrane 152 can be elastomeric and canuse at least in part its material properties to naturally or elasticallyreturn to the its original position on the bottom of the housing 148.The membrane 152 can have any desired shape. In other embodiments, theweight of the prosthesis or foot 120 below the pump mechanism 126 canhelp move the pump mechanism 126 toward the original configuration.

Optionally, the pump mechanism 126 can include a biasing mechanism 164arranged to bias the pump mechanism 126 toward the originalconfiguration. The biasing mechanism 164 can comprise a ring memberhaving a compressible configuration situated in the cavity 138. Thebiasing mechanism 164 can be resilient such as an elastomeric materialand/or any other material that deforms under a load and returns to itsoriginal form or position when the load is released. During weightbearing, the biasing mechanism 164 can compress between the housing 148and the upper section 130. After weight bearing, the biasing mechanism164 can decompress and stored energy in the biasing mechanism 164 candrive the pump mechanism 126 toward the original configuration.

The pump mechanism 126 can thus generate a vacuum in the socket 114during stance without undesirably affecting the functionality of theprosthetic foot 120 or significantly increasing the bulk of theprosthetic device. In addition, the pump mechanism 126 canadvantageously provide a dampening or shock absorbing effect to theprosthetic device, allowing for a more comfortable gait cycle.

According to a variation, at least one sensor can be incorporated intothe pump system 112. For instance, the pump system 112 can include atleast one sensor 129 including, but not limited to, one or more HallEffect sensors, linear variable displacement transducers, differentialvariable reluctance transducers, or reed switches. The at least onesensor 129 can be incorporated in the upper section 130 and/or the lowersection 132 and arranged to measure one or more relationships betweenthe two components. For instance, the at least one sensor 129 can beused to measure force or positional changes between the upper and lowersections 130, 132. In an embodiment, a Hall Effect sensor can be used tomonitor angular changes between the upper and lower sections 130, 132.The output from the at least one sensor 129 can be used to regulatepressure in the socket 114. In other embodiments, the output from the atleast one sensor 129 can be used for general sensory feedbackinformation on gait and performance characteristics.

FIGS. 13-15 illustrate a pump system 163 according to another embodimentthat can be integrated in the adaptor system of a prosthetic device. Inthe illustrated embodiment, the pump system 163 can comprise aprosthetic connector adapted to form a connection between a prostheticfoot and a socket. The pump system 163 can include a pump mechanism 164,an upper section 172, and a lower section 174. At least one of the upperand lower sections 172, 174 is movable axially relative to the other.The upper section 172 can include an adaptor 176 and the lower section174 can include an adaptor 178. The adaptors 176, 178 are shown asfemale adaptors but can be male adaptors or other types of connectors.

The pump mechanism 164 includes a housing 166, a membrane 168, and aconnector 170. It will be appreciated that the pump mechanism 164 mayinclude one or more valve assemblies similar to the other embodimentsarranged to control movement of fluid into and from the pump mechanism126. Referring to FIG. 14, the housing 166 can be located in the uppersection 172. The housing 166 defines a cavity 180 provided with anundercut circumferential groove 182 between an open end of the cavity182 and a closed end 184 of the cavity 180. An outer radial edge portionof the membrane 168 can be situated in the circumferential groove 182such that a seal is formed between the membrane 168 and the housing 166.The closed end 184 of the cavity 180 can define one or more openingswhich extend into the housing 166 to form internal passageways providingfluid communication between a fluid chamber defined below and one ormore valve assemblies.

The pump mechanism 164 is movable between an original configuration(FIG. 14) in which the volume of a fluid chamber 186 defined between thebottom surface of the membrane 168 and the closed end 184 of the cavity180 is zero or near-zero, and an expanded configuration (shown in FIG.15) in which the volume of the fluid chamber 186 is increased. Thebottom 184 of the cavity 180 substantially complements the bottomsurface of the membrane 168 such that when no force is exerted on thepump mechanism 164 it is in the original position.

The lower section 174 includes a base 188 and arms 190 on each side ofthe base 188 that extend upwardly from the base 188. A cross member 192is formed between the arms 190. The cross member 192 extends through anopen space 194 formed of the upper section 174 over the housing 166. Aresilient element 196 connects the upper section 172 to the lowersection 174. The resilient element 196 can be a spring member. Thespring member can have a folded structure.

The membrane 168 may have any desired shape, but is shown having agenerally circular or elliptical shape. The membrane 168 can beoperatively attached at or near its center point to the cross member 192of the lower section 174 while the outer radial edge portion of themembrane 168 is attached to the upper section 172 such that when themembrane 168 is pulled away from the upper section 172 a pocket forms ina middle area of the membrane 168 due to the deformation of the membrane168. The formation of the pocket increases the volume of the fluidchamber 186.

During weight bearing or when a load is applied to a socket or pylon(e.g., in stance phase), the upper section 172 moves downward relativeto the lower section 174 as shown in FIG. 15. This pulls the membrane168 away from the housing 166, moving the pump mechanism 164 toward theexpanded configuration. More particularly, the cross member 192 pullsthe membrane 168 away from the closed end 184 of the cavity 180 todeform the membrane 168 between the cross member 192 and the uppersection 172, increasing the volume of the fluid chamber 186.

After weight bearing or when the load is removed (e.g., in swing phase),the pump mechanism 164 returns toward the original configuration as theupper section 172 moves upward relative to the lower section 174 asshown in FIG. 14. This allows the membrane 168 to return toward thebottom 184 of the cavity 180, expelling fluid within the fluid chamber186 out of the fluid chamber 186.

The resilient element 196 can be a biasing mechanism arranged to biasthe pump mechanism 164 toward the original configuration. During weightbearing, the resilient element 196 can compress between the uppersection 172 and the lower section 174. After weight bearing, theresilient element 196 can decompress and stored energy in the biasingmechanism 196 can drive the pump mechanism 164 toward the originalconfiguration.

The connector 170 can include a lower radial flange 198 embedded in themembrane 168, an upper radial flange 202 above the membrane 168 andattached to the cross member 192, and a shaft portion 204 extendingbetween the lower flange 198 and the upper flange 202. In someembodiments, the connector 170 may be of a two-piece construction suchthat the upper flange 202 can be threadedly removed from the lowerflange 198 embedded in the membrane 168. The cross member 192 can definean opening for attaching the connector 170 to the cross member 192.

The pump mechanism 164 can thus generate a vacuum in a socket duringstance without significantly increasing the bulk of the prostheticdevice. It can also provide a dampening or shock absorbing effect to theprosthetic device.

FIGS. 16-18 illustrate a pump system 205 according to another embodimentthat can be integrated in an adaptor system of a prosthetic device. Forinstance, the pump system 205 can comprise a prosthetic connector. Thepump system 205 includes a pump mechanism 206, an upper section 218, anda lower section 220. At least one of the upper and lower sections 218,220 is arranged to move axially relative to the other. The upper section218 can include an adaptor 222 and the lower section 220 can include anadaptor 224. The adaptors 222, 224 are shown as female adaptors but canbe male adaptors or other types of prosthetic connector.

The upper section 218 can be connected to the lower section 220 via aresilient element comprising a flexible enclosure 226. The flexibleenclosure 226 includes a generally horizontal top 226A attached to theupper section 218 and a generally horizontal bottom 226B attached to thelower section 220. The top and bottom 226A, 226B are connected togetherby convex side 226C, 226D. The top 226A, bottom 226B, and sides 226C,226D collectively define an inner space 227 of the flexible enclosure226. The flexible enclosure 226 can be made of a durable but flexiblematerial such as carbon fiber cloth, unidirectional composites, plastic,and/or metal. The configuration of the flexible enclosure 226 can beadjusted based on the weight of the user and/or other factors. Theflexible enclosure 226 can be formed of a single part, two parts, threeparts, or any other suitable number of parts.

Similar to the other embodiments, the pump mechanism 206 can include ahousing 208, a membrane 210, and one or more valve assemblies arrangedto allow fluid to enter and exit the pump mechanism 206.

The pump mechanism 206 can be situated within the inner space 227 of theflexible enclosure 226. The flexible enclosure 226 can be attached tothe housing 208 via a first connector 228 extending between the housing208 and the side 226C of the flexible enclosure 226. The flexibleenclosure 226 can be attached to a center portion of the membrane 210via a second connector 230 extending between the membrane 210 and theside 226D of the flexible enclosure 226.

FIGS. 17 and 18 show cross section views of the pump mechanism 206. Thepump mechanism 206 relies upon deformation of the membrane 210 to movebetween an original configuration (shown in FIG. 17) in which the volumeof a fluid chamber 228 defined between the housing 208 and the membrane210 is zero or near-zero, and an expanded configuration (shown in FIG.18) in which the volume of the fluid chamber 228 is increased. Themembrane 210 can be positioned in a cavity 212 of the housing 208. Thehousing 208 surrounds the outer radial edge portion of the membrane 210and creates a seal with the membrane 210. The bottom of the cavity 212can define one or more openings to form internal passageways to providefluid communication between the fluid chamber 228 and the one or morevalve assemblies.

During weight bearing or when a load is applied to the socket (e.g., instance phase), the pump mechanism 206 moves toward the expandedconfiguration (shown in FIG. 18). More particularly, the upper section218 and the lower section 220 move toward one another, which, in turn,causes the flexible enclosure 226 to compress between the upper andlower sections 218, 220. When the flexible enclosure 226 compresses, thesides 226C, 226D of the flexible enclosure 226 bow out or are forcedapart, which in turn, causes at least the second connector 230 to pullthe membrane 210 away from the bottom of the cavity 212, increasing thevolume of the fluid chamber 228. This increase in volume of the fluidchamber 228 creates a vacuum in the pump mechanism 206, pulling fluidinto the pump mechanism 206. Weight bearing on a prosthetic device thusautomatically creates a vacuum in the pump mechanism 206. It will beappreciated that in other embodiments the membrane 210 can be pulledaway from the bottom of the cavity 212 by the first connector 228 or thefirst and second connectors 228, 230 together.

After weight bearing or when the load is removed (e.g., in swing phase),the pump mechanism 206 can return toward the original configuration(shown in FIG. 17). Stored energy in the flexible enclosure 226 forcesthe upper and lower sections 218, 220 away from one another. This movesthe first and second sides 226A, 226B back toward one another, forcingthe membrane 210 toward the bottom of the cavity 212 and expel fluidwithin the fluid chamber 238 out of the pump mechanism 206. As such, theflexible enclosure 226 can both move the pump mechanism 206 between theoriginal and expanded configurations when loaded, and bias the pumpmechanism 206 from the expanded configuration toward the originalconfiguration.

The pump system 205 can thus generate a vacuum in a socket in responseto a load on the socket or pylon without undesirably affecting thefunctionality of a prosthetic foot or significantly increasing the bulkof the prosthetic device.

FIG. 19 illustrates a pump system 240 according to another embodiment.It will be similar that the pump system 240 is similar in structure andfunction to the pump system 205 except that the flexible enclosure has adifferent shape. For instance, the pump system 240 includes a pumpmechanism 242, an upper section 244, and a lower section 246. The uppersection 244 and lower section 246 are connected to one another via aresilient element comprising a flexible enclosure 248.

In the illustrated embodiment, the flexible enclosure 248 includes afirst part 250 and a second part 252 spaced from the first part 250.Each of the first and second parts 250, 252 includes a top 254 attachedto the upper section 244, a bottom 256 attached to the lower section246, and a convex intermediate segment 258 extending between the top 254and the bottom 256. The top 254 extends radially inward from an outeredge of the upper section 244 to where it connects with the intermediatesegment 258 near a middle of the upper section 244. The bottom 256 alsoextends radially inward from an outer edge of the lower section 246 towhere it connects with the intermediate segment 258 near a middle of thelower section 246.

During weight bearing, the upper and lower sections 244, 246 move towardone another, which, in turn, causes the flexible enclosure 248 tocompress. When the flexible enclosure 248 compresses, the intermediatesegments 258 of the first and second parts 250, 252 bow out or areforced apart, which, in turn, moves the pump mechanism 242 toward theexpanded configuration. After weight bearing, stored energy in theflexible enclosure 248 forces the upper and lower sections 244, 246 awayfrom one another. This moves the intermediate segments 258 back towardone another, returning the pump mechanism 242 toward the originalconfiguration.

FIGS. 20 and 21 illustrate a pump system 260 according to anotherembodiment that can be integrated in an adaptor system of a prostheticdevice. For instance, the pump system 260 can comprise a prostheticconnector. The pump system 260 includes a pump mechanism 262, an uppersection 264, and a lower section 266. At least one of the upper andlower sections 264, 266 is arranged to move axially relative to theother. In the illustrated embodiment, the upper section 264 has a femaleconfiguration and the lower section 266 has a male configurationarranged to fit in the upper section 264. As seen, the upper section 264can include an adaptor 268 and the lower section 266 can include anadaptor 270. The adaptors 268, 270 are shown as male adaptors but can befemale adaptors or any other type of connector.

The lower section 266 defines a cavity 272 having a peripheral internalcavity wall 274 extending between a top opening at or near the top ofthe lower section 266 and a closed end 276. The cavity 272 is shownhaving a generally cylindrical shape but can have any suitable shape. Achannel 278 extends through the lower section 266 and traverses thecavity 272.

The upper section 264 defines a cavity 280 having a peripheral internalcavity wall 282 extending between a bottom opening 284 at or near thebottom of the upper section 264 and a closed end 286. The lower section266 is sized and configured to be received in the cavity 280 of theupper section 264. The upper section 264 includes a cross member 288extending through the channel 278 of the lower section 266. The crossmember 288 can be a pin member. The cross member 288 can extend in agenerally horizontal direction. The channel 278 and the cross member 288can be sized and configured such that the cross member 288 can move upand down within the channel 278 but also holds the upper section 264 onthe lower section 266. The range of axial movement between the upper andlower sections 264, 266 can be limited by a height of the channel 278and/or the cross member 288.

The pump mechanism 262 is positioned on the top of the lower section 266within the cavity 280 of the upper section 264. The pump mechanism 262includes a housing 290, a membrane 292, and a connector 294. The pumpmechanism 262 may include one or more valve assemblies 296 arranged tocontrol movement into and from the pump mechanism 262. According to avariation, a fluid passageway 298 is defined in the adaptor 268 of theupper section 264 that is fluid communication with the pump mechanism262. This facilitates fluid entering and exiting the pump mechanism 262to pass through the adaptor 268.

The housing 290 defines a cavity 302 provided with an undercutcircumferential groove 304 between an open end of the cavity 302 and aclosed end 306 of the cavity 302. An outer radial edge portion of themembrane 292 can be situated in the circumferential groove 304 such thata seal is formed between the membrane 292 and the housing 290. A centerportion of the membrane 292 can be attached to the cross member 288 ofthe upper section 264. For instance, the connector 294 can attach thecenter portion of the membrane 292 to the cross member 288. The closedend 306 of the cavity 302 can define one or more openings which extendinto the housing 290 to form internal passageways providing fluidcommunication between the one or more valve assemblies 296 and a fluidchamber defined below.

The pump mechanism 262 is movable between an original configuration(FIG. 20) in which the volume of a fluid chamber 308 defined between thetop of the membrane 292 and the closed end 306 of the cavity 302 is zeroor near-zero, and an expanded configuration (shown in FIG. 21) in whichthe volume of the fluid chamber 308 is increased.

During weight bearing or when a load is applied to a socket or pylon,the upper section 264 moves downward relative to the lower section 266as shown in FIG. 21. This pulls the membrane 292 away from the closedend 306 of the cavity 302, moving the pump mechanism 262 toward theexpanded configuration. More particularly, the cross member 288 of theupper section 264 moves downward within the channel 278 and pulls thecenter portion of the membrane 282 away from the closed end 306 of thecavity 302 to deform the membrane 282, increasing the volume of thefluid chamber 308.

After weight bearing or when the load is removed, the pump mechanism 262can return toward the original configuration as the upper section 264and cross member 288 move upward relative to the lower section 266 asshown in FIG. 20. This allows the membrane 292 to return towards theclosed end 306 of the cavity 302, expelling fluid within the fluidchamber 308.

According to a variation, the pump system 260 can include a biasingmechanism 310 arranged to bias the pump mechanism 262 toward theoriginal configuration. The biasing mechanism 310 can comprise a springmember disposed between the closed end 276 of the lower section 266 andthe cross member 288 of the upper section 264. In an embodiment, thespring member can be positioned on a stem portion extending downwardlyfrom the cross member 288. When the pump system 260 is loaded, thebiasing mechanism 310 can compress between the closed end 276 of thelower section 266 and the cross member 288 of the upper section 264.When the pump system 260 is unloaded, the biasing mechanism 310 candecompress and stored energy in the biasing mechanism 310 can drive thepump mechanism 260 toward the original configuration.

According to a variation, the housing 290 can be threadedly attached tothe lower section 266. For instance, the housing 290 can define aplurality of external threads arranged to mesh with a plurality ofinternal threads defined by the lower section 266. In an embodiment, theadaptor portion 268 can be threadedly attached to the upper section 264and the adaptor portion 270 can be threadedly attached to the lowerportion 266.

FIGS. 22-24 illustrate a pump system 312 according to another embodimentthat can be integrated in an adaptor system of a prosthetic device. Inan embodiment, the pump system 312 can comprise a prosthetic connector.The pump system 312 includes a pump mechanism 314, an upper section 316,and a lower section 318. At least one of the upper and lower sections316, 318 is arranged to move relative to the other. In an embodiment,the upper section 316 includes an adaptor 320 and the lower section 318includes an adaptor 322. The adaptors 320, 322 are shown as femaleadaptors but can be male adaptors or any other suitable connectors.

A resilient element 324 connects the upper section 316 and the lowersection 318. The resilient element 324 can be any suitable member but isshown as a blade having a semicircular configuration with an upper arm326 attached to the upper section 316 and a lower arm 328 attached tothe lower section 318.

The pump mechanism 314 is positioned between the upper and lowersections 316, 318. The pump mechanism 314 includes a housing 330 and amembrane 332. The pump mechanism 314 may include one or more valveassemblies 334 arranged to control movement of fluid into and from thepump mechanism 314. The housing 330 defines an internal passageway 336providing fluid communication between the one or more valve assemblies334.

An outer edge portion of the membrane 332 is attached to the housing 330such that a seal is formed between the membrane 332 and the housing 330.A center portion of the membrane 332 can be attached to the upper arm326 of the resilient element 324.

The pump mechanism 314 is movable between an original configuration(shown in FIG. 23) in which the volume of a fluid chamber 338 definedbetween the bottom of the membrane 332 and the housing 330 is zero ornear-zero, and an expanded configuration (shown in FIG. 24) in which thevolume of the fluid chamber 338 is increased.

During moment or rotation of the upper and lower sections 316, 318 awayfrom one another (e.g., after heel strike), the pump mechanism 314 movestoward the expanded configuration. More particularly, the upper arm 326of the resilient element 324 pulls the center portion of the membrane332 away from the housing 330, increasing the volume of the fluidchamber 338. This increase in volume of the fluid chamber 338 creates avacuum in the pump mechanism 314, pulling fluid into pump mechanism 314through the one or more valve assemblies 334.

During moment or rotation of the upper and lower sections 316, 318toward one another, the pump mechanism 314 moves toward the originalconfiguration. More particular, the resilient element 324 forces thepump mechanism 314 toward the original configuration and decreases thevolume of the fluid chamber 338. During the return of the membrane 332toward the housing 330, the pump mechanism 314 expels fluid in the fluidchamber 338 out of the one or more valve assemblies 334.

FIGS. 25 and 26 illustrate a pump system 340 according to anotherembodiment that can be integrated in an adaptor system of a prostheticdevice. As seen, the pump system 340 can comprise a prostheticconnector. The pump system 340 includes a pump mechanism 342, an uppersection 344, and a lower section 346. The upper section 344 is arrangedto move axially relative to the pump mechanism 342 and the lower section346. According to a variation, the upper section 344 includes an adaptor348 and the lower section 346 includes an adaptor 350. The adaptors 348,350 are shown as male adaptors but can be female adaptors or any othersuitable connectors. The upper section 344 includes a pin member 352extending in a downward direction and a through-hole 360. A horizontalmember 361 attached to the lower section 346 and protrudes through thethrough-hole 360 of the upper section 344 to help maintain the uppersection 344 on the lower section 346. The through-hole 360 and thehorizontal member 361 can be sized and configured such that thehorizontal member 361 can move up and down within the through-hole 360.

The pump mechanism 342 is attached to an upper surface of the lowersection 346 and positioned within an open cavity 354 defined by theupper section 344. The pump mechanism 342 includes a housing 356 and amembrane 358. The pump mechanism 342 may include one or more valveassemblies similar to the other embodiments arranged to control movementof fluid into and from the pump mechanism 342. The housing 356 candefine passageways providing fluid communication between the one or morevalve assemblies.

The housing 356 can define an internal chamber 362 and through opening364 arranged to allow the pin member 352 to pass therethrough. Themembrane 358 is disposed in the internal chamber 362. An outer edge ofthe membrane 358 of the membrane 358 is attached to the upper internalwall of the internal chamber 362. A center portion of the membrane 358can be attached to the pin member 352.

The pump mechanism 342 is movable between an original configuration(shown in FIG. 25) in which the volume of a fluid chamber 366 definedbetween the top of the membrane 358 and the housing 356 is zero ornear-zero, and an expanded configuration (shown in FIG. 26) in which thevolume of the fluid chamber 366 is increased.

During weight bearing or when a load is applied to a socket or pylon,the upper section 344 moves downward relative to the lower section 346,which, in turn, causes the pin member 352 to push the center portion ofthe membrane 358 away from the upper internal wall of the internalchamber 362, increasing the volume of the fluid chamber 366. Thisincrease in volume of the fluid chamber 366 creates a vacuum in the pumpmechanism 342, pulling fluid into the pump mechanism 342. Weight bearingon a prosthetic device thus automatically creates a vacuum in the pumpmechanism 342.

After weight bearing, the pump mechanism 342 returns toward the originalconfiguration as the upper section 344 moves upward relative to thelower section 346. This moves the pin member 352 in the upwarddirection, pulling the membrane 358 toward the upper internal wall ofthe internal chamber 362 and expelling fluid within the fluid chamber366 out of the pump assembly 342.

According to a variation, the pump system 340 can include a biasingmechanism 368 arranged to bias the pump mechanism 342 toward theoriginal configuration. The biasing mechanism 368 can comprise a springmember positioned between the bottom of the membrane 358 and the bottomof the internal chamber 362. During weight bearing, the biasingmechanism 368 can compress between the membrane 358 and the bottom ofthe housing 356. After weight bearing, the biasing mechanism 368 candecompress and stored energy in the biasing mechanism 368 can drive thepump mechanism 342 toward the original configuration.

The pump mechanism 342 can thus generate a vacuum in a socket duringstance without undesirably affecting the functionality of the prostheticfoot or significantly increasing the bulk of the prosthetic device. Inaddition, the pump mechanism 342 can advantageously provide a dampeningor shock absorbing effect to the prosthetic device, allowing for a morecomfortable gait cycle.

FIGS. 27 and 28 show a vacuum suspension system 375 comprising a pumpsystem 370 and a foot cover 372 according to another embodiment. Thepump system 370 can include a pump mechanism 374 (shown in FIG. 28)disposed in a heel portion 376 of the foot cover 372 and a tube system378 integrated with the foot cover 372. The tube system 378 is in fluidcommunication with the pump mechanism 374 and a socket. In anembodiment, the tube system 378 can extend from the heel portion 376 andthrough a hole 380 formed in a top portion of the foot cover 372defining a foot opening of the foot cover 372.

FIG. 28 is a cross section view of the vacuum suspension system 375. Thepump system 370 can be similar to the pump system 340 except the upperand lower sections 382, 384 do not include adaptors. As seen, the pumpmechanism 374 utilizes the space within the body of the foot cover 372such that it does not add any additional volume to the prosthetic deviceor the foot cover 372. In addition, the pump mechanism 374 can easilyretrofit to existing foot covers and can be formed to be used with rightor left foot covers. In addition, because the pump system 370 is formedwithin a thickness of the foot cover 372, it reduces the likelihood ofthe pump system 370 undesirably affecting the functionality of aprosthetic foot, providing a more natural gait.

The pump mechanism 374 can be in fluid communication with one or morevalve assemblies 384 associated with the tube system 378. Similar to theother embodiments, the one or more valve assemblies 384 are arranged tocontrol fluid flow into and out of the pump mechanism 374.

The pump mechanism 374 is movable between an original configuration inwhich the volume of a fluid chamber 386 defined between a membrane 388and a housing 390 is zero or near-zero, and an expanded configuration inwhich the volume of the fluid chamber 386 is increased.

During gait or when a load is applied to the foot cover 372, the uppersection 382 moves downward relative to the lower section 384, which, inturn, causes a pin member 392 to push the center portion of the membrane388 away from the housing 390, increasing the volume of the fluidchamber 386. This increase in volume of the fluid chamber 386 creates avacuum in the pump mechanism 374, pulling fluid into the pump mechanism374. Weight bearing during gait thus automatically creates a vacuum inthe pump mechanism 374.

After weight bearing, the pump mechanism 374 returns toward the originalconfiguration as the upper section 382 moves upward relative to thelower section 384. This moves the pin member 392 in the upwarddirection, pulling the membrane 388 toward the upper wall of the housing290 and expelling fluid within the fluid chamber 386 out of the pumpassembly 374.

According to a variation, the pump system 370 can include a biasingmechanism 394 arranged to bias the pump mechanism 374 toward theoriginal configuration. The prosthetic device thus automatically createsa vacuum in the pump mechanism 374 during stance and automaticallyexpels fluid to atmosphere during the swing phase.

While the pump system is generally described as being separate from aprosthetic foot, in other embodiments, the pump system can be adapted tobe located on the prosthetic foot. For instance, FIG. 29 shows a vacuumsuspension system 395 comprising a pump system 396, a prosthetic foot398, and a foot cover 402 according to another embodiment.

The prosthetic foot 398 has an upper foot member 404 and a lower footmember 406, which is disposed generally below the upper foot member 404.The prosthetic foot 398 can have a heel member 408 that extendsrearwardly to a free end and is disposed below at least a portion of thelower foot member 406. The prosthetic foot 398 may be insertable intothe foot cover 402 as seen. In use, the prosthetic foot 398 can expandand compress.

The pump system 396 includes a pump mechanism 410 that is operablebetween the heel member 408 and a support member 412 coupled to the footcover 402. The pump mechanism 410 can be positioned in the space betweenthe heel member 408 and the bottom surface of the lower foot member 406,making it unlikely that the pump mechanism 410 will negatively affectthe functionality of the prosthetic foot 398. Further, the pumpmechanism 410 can be formed to be used with both left and rightprosthetic feet.

Similar to the other embodiments, the pump mechanism 410 includes ahousing 414 containing two one-way valve assemblies 416, 418, amembrane, and a connector. The valve assembly 416 only allows fluid toenter the pump mechanism 410 which can be in fluid communication withthe cavity of a socket. The valve assembly 418 only allows fluid to beexpelled out of the pump mechanism 410, preferably to atmosphere. Theconnector can be attached to the membrane and the heel member and canexhibit any suitable configuration. For instance, the connector may be asingle fastener or screw, allowing the pump mechanism 410 to easilyretrofit on a prosthetic foot. The housing 414 can be attached to thesupport member 412.

Similar to the previously described pump mechanisms, the pump mechanism410 relies upon deformation of the membrane to move between an originalconfiguration in which the volume of a fluid chamber defined between anupper surface of the membrane and the bottom of the housing 414 is zeroor near-zero, and an expanded configuration in which the volume of thefluid chamber is increased.

The housing 414 is arranged to surround the outer radial edge portion ofthe membrane and creates a seal with the membrane. The bottom of thehousing 414 defines a pair of openings which extend into the housing 414to form internal passageways to provide fluid communication between thefluid chamber and the two one-way valve assemblies 416, 418.

The support member 412 can be coupled to the foot cover 402. The supportmember 412 can be any suitable member but is shown as a metal rod havinga cross member 420 extending in a transverse direction across the footcover 402 above the heel member 408 and side members 422 extendingdownwardly along the sides of the foot cover 402 toward the ground.According to a variation, the foot cover 402 can include one or morereinforcements where the side members 422 extend along the sides of thefoot cover 402. The outer surface of the foot cover 402 can define slots424 to receive the side members 422 of the support member 412, helpingto maintain the position of the support member 412 on the foot cover402. This also lowers the profile of the support member 412, reducingthe likelihood of the support member 412 interfering with footwear.

The support member 412 can be pivotally connected to the housing 414.For instance, the cross member 420 of the support member 412 can extendthrough a channel or hole 426 defined by the housing 414 such that thehousing 414 is pivotally connected to the support member 412.

Upon heel strike, the prosthetic foot 398 moves into expansion, which,in turn, causes the heel member 408 and the cross member 420 of thesupport member 412 to move apart. This separation causes the housing 414to pivot around the cross member 420, which, in turn, rotates thehousing 414 away from the heel member 408.

As the housing 414 rotates away from the heel member 408, the heelmember 408 pulls the membrane away from the housing 414, increasing thevolume of the fluid chamber. This increase in volume of the fluidchamber creates a vacuum in the pump mechanism 410, pulling fluid intothe pump mechanism 410 through the valve assembly 104. Expansion of theprosthetic foot thus automatically creates a vacuum in the pumpmechanism 410.

As the prosthetic foot 398 moves from heel strike through mid-stanceand/or toe-off, the prosthetic foot 398 moves into compression. Incompression, the heel member 408 and the cross member 420 of the supportmember 412 move toward one another, which, in turn, forces the pumpmechanism 410 back toward its original configuration and decreases thevolume of the fluid chamber to a zero or near-zero volume.

During the return of the membrane toward the housing 414, the pumpmechanism 410 expels fluid in the fluid chamber out of the valveassembly 424. Because the pump mechanism 410 returns to its originalconfiguration of zero or near-zero volume in the fluid chamber atmid-stance and/or toe-off, all fluid drawn into the pump mechanism 410can be automatically expelled rather than relying on completecompression cycle of the pump to expel air drawn in from the socket asin the prior art.

According to a variation, the pump system 396 can include a biasingmechanism 428 arranged to help the pump mechanism 410 return to itsconfiguration. For instance, at least one band member having anelastomeric configuration can extend around the heel member 408 and thehousing 414, biasing the housing 414 toward the heel member 408 and/orbiasing the support member 412 and the foot cover 402 together.

It will be appreciated that the prosthetic devices described herein areto be regarded as exemplary only, as any prosthetic device is possible.For instance, while the valve assemblies are described being attached tothe housing, in other embodiments, one or more of the valve assembliescan be in fluid communication with the pump mechanism via a tubularfluid conduit. It will be appreciated that the housing can be made ofany suitable material such as carbon fiber cloth, unidirectionalcomposites, plastic, or metal. It will be appreciated that embodimentsof the pump system described herein can include at least one sensor(e.g., a Hall Effect Sensor or gap-sensor) arranged to measure one ormore relationships such as displacement or force between two componentsof the pump system. For instance, the at least one sensor can beincorporated in the upper section 268 and/or the lower section 270 ofthe pump system 260. Output from the at least one sensor can be used toregulate pressure in a socket, for general sensory feedback informationon gait and performance characteristics, or for another suitablepurpose.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments are contemplated. The various aspects andembodiments disclosed herein are for purposes of illustration and arenot intended to be limiting. Additionally, the words “including,”“having,” and variants thereof (e.g., “includes” and “has”) as usedherein, including the claims, shall be open ended and have the samemeaning as the word “comprising” and variants thereof (e.g., “comprise”and “comprises”).

1. A vacuum suspension system comprising: a foot cover having a heelportion; and a pump system located in the heel portion, the pump systemincluding: upper and lower sections arranged to move in an axialdirection relative to one another; and a pump mechanism operativelyconnected to and positioned between the upper and lower sections suchthat when the heel portion is loaded in stance the pump mechanism movesfrom an original configuration in which the volume of a fluid chamberdefined by the pump mechanism is zero or near-zero, to an expandedconfiguration in which the volume of the fluid chamber is increased. 2.The vacuum suspension system of claim 1, wherein a biasing mechanismarranged to bias the pump mechanism toward the original configuration.3. The vacuum suspension system of claim 2, wherein the biasingmechanism is located between the upper and lower sections.
 4. The vacuumsuspension system of claim 1, wherein the pump mechanism includes ahousing defining a cavity and a membrane situated in the cavity suchthat the fluid chamber is defined between the membrane and the housing.5. The vacuum suspension system of claim 4, wherein deformation of acenter portion of the membrane varies the volume of the fluid chamber.6. The vacuum suspension system of claim 4, wherein the upper sectiondefines a pin member arranged to engage a center portion of themembrane.
 7. The vacuum suspension system of claim 6, wherein thehousing defines an opening arranged to allow the pin member slidablypass therethrough.
 8. The vacuum suspension system of claim 1, whereinthe pump system is concealed within the foot cover.
 9. The vacuumsuspension system of claim 1, wherein the pump mechanism is locatedwithin a thickness of the heel portion.
 10. The vacuum suspension systemof claim 1, further comprising one or more valve assemblies arranged tocontrol fluid flow into and out of the pump mechanism.
 11. The vacuumsuspension system of claim 1, wherein the pump mechanism moves towardthe original configuration when the foot cover is unloaded.
 12. Thevacuum suspension system of claim 11, wherein the upper section movesupward relative to the lower section when the foot cover is unloaded.13. The vacuum suspension system of claim 1, further comprising a socketconnected to and in fluid communication with the pump mechanism.
 14. Thevacuum suspension system of claim 13, wherein a tube system fluidlyconnects the pump mechanism to the socket.
 15. The vacuum suspensionsystem of claim 13, wherein the tube system extends from the heelportion through a hole formed in a top portion of the foot cover.
 16. Avacuum suspension system comprising: a pump system arranged to be influid communication with a prosthetic socket, the pump system includinga pump mechanism having a housing and a membrane situated on the housingsuch that a fluid chamber is defined between the membrane and thehousing, the pump mechanism movable between an original configuration inwhich the volume of the fluid chamber is zero or near-zero, and anexpanded configuration in which the volume of the fluid chamber isincreased, wherein the housing is pivotally connected to a supportmember extending in a transverse direction across a foot cover.
 17. Thevacuum suspension system of claim 16, wherein the support membercomprises a metal rod attached to a foot cover.
 18. The vacuumsuspension system of claim 16, wherein the pump mechanism moves towardthe expanded configuration when the housing rotates away from a heelportion of the foot cover.
 19. The vacuum suspension system of claim 18,wherein the pump mechanism moves toward the expanded configuration whenthe housing rotates toward the heel portion of the foot cover.
 20. Avacuum suspension system comprising: a prosthetic socket; a foot coverhaving a heel portion; and a pump system located in the heel portion andin fluid communication with the prosthetic socket, the pump systemincluding: upper and lower sections arranged to move in an axialdirection relative to one another; and a pump mechanism operativelyconnected to and positioned between the upper and lower sections suchthat when the heel portion is loaded in stance the pump mechanism movesfrom an original configuration in which the volume of a fluid chamberdefined by the pump mechanism is zero or near-zero, to an expandedconfiguration in which the volume of the fluid chamber is increased.